Is profound hypothermia required for storage of cardiac allografts?

Background: Improved methods of cardiac allograft protection are required t o expand the pool of potentially available organs and to enhance the recove ry of grafts subjected to prolonged ischemia. We have previously demonstrat ed that limited coronary perfusion provided by donor blood harvested at the time of organ procurement can improve both metabolic and functional recove ry after transplantation. In this study we evaluated the hypothesis that li mited coronary perfusion may enable prolonged cardiac storage while avoidin g the potentially detrimental effects of profound hypothermia. Methods: Fourteen orthotopic cardiac transplants were performed in female Y orkshire pigs by using donor blood perfusion during 5 hours of either tepid (25 degreesC) or cold (4 degreesC) storage. Assessments of myocardial meta bolism and function were performed at baseline and after 45 minutes of norm othermic (37 degreesC) reperfusion. Results: Hearts protected with tepid perfusion displayed improved recovery of myocardial function (89% +/- 18% vs 63% +/- 25%, P =.05). Diastolic comp liance was adversely affected in both groups after transplantation. Aerobic myocardial metabolism was better preserved in the tepid group. Conclusions: Profound hypothermia results in depressed myocardial metabolic and functional recovery after transplantation. Limited coronary perfusion with shed donor blood can permit cardiac allograft storage at tepid tempera tures, resulting in improved myocardial performance.